I'm surprised there isn't something available for the iPhone. It's a very popular device and the worldwide LF community isn't all that tiny. And it seems to be growing.
In fact, it's the whole film community that would be the target, not just the ones with the inconvenient cameras.
I use that lens as a long focal length for 5x4. When I began shooting 10x8 in the early 80's, my first and only lens at the time was a 12" Kodak Commercial Ektar. It was a fine lens, but my eye just didn't want to conform to a normal focal length. So, I sold the Ektar and bought a 360mm Schneider Symmar-S; a massive piece of glass for sure! Used that lens for decades, but my advancing years seem to demand that I lighten my load! So, I entered my pledge for the Intrepid 10x8 Mk I and waited... During that time, I lucked into a 360mm Fuji A which I always wanted, but they're a bit hard to come by. Nowadays, it's my absolute favorite lens for 10x8.I prefer a 300mm Nikkor M for 8x10 though